Some electrical devices such as power tools, electrical vehicles and other portable devices may be powered by battery packs. By attaching a cordless battery pack to a power tool, a user is free to move about without being constrained by a power cord.
A battery pack may include battery cells and switching circuitry for allowing the battery cells to supply power or be charged. One or more monitoring functions may be performed by circuitry included in the battery pack to maintain a safe use of the battery cells. For example, the voltage levels present on each battery cell may be monitored.
Certain battery cell chemistries e.g., lithium-ion cells, may become hazardous if their voltage level exceeds a high voltage threshold or drops below a low voltage threshold. Accordingly, conventional circuitries may monitor battery cell voltage and compare the monitored voltage to predefined low and high voltage thresholds. If either threshold is reached, a safety function (e.g., increase monitoring rate, open a switch, etc.) may be initiated. However, determining that a threshold breech may take a considerable period of time, and such a long period of time may exceed safety limits of the battery.